• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.676-683
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• 2000

For high quality storage of agricultural products, temperature, humidity and gas conditions in a storage house should be controlled properly. But most of the low temperature storage house is depending on temperature control. This study aimed to develop an automatic control system for low temperature storage house that can control storage conditions such as temperature, humidity and $CO_2$ gas concentration. The developed system alarms the user, by telephone or beeper, when abnormal condition has occurred. The farmer can also monitor the inside condition of warehouse in his residence, by Internet. From the results of the performance test, the temperature and relative humidity in the warehouse is controlled within the range of ${\pm}0.5^{circ}C$ and ${\pm}2%$, respectively.

• 생물환경조절학회지
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• 제16권3호
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• pp.247-251
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• 2007

신선 엽채류인 시금치의 수확 후 포장, 저장유통온도별 품질보존 및 상품성에 미치는 영향을 조사하였다. 저장 중 중량의 변화에서 포장 후 저장 시는 중량감소가 거의 없었으나, 무포장은 저장기간이 길어질수록 그리고 저장온도가 높을수록 감소율이 현저하였다. 비타민 C함량은 저장 초기에 감소가 컸으며, 저장온도가 낮을수록 감소가 적었고, 비닐포장 간에는 큰 차이가 없었다. 시금치에서 Hunter's value는 저장온도가 높을수록 b값이 높아지는 경향이었다. 시금치 저장 중 외관 신선도에서 polypropylene 비닐포장 후 저온$(1{\sim}3^{\circ}C)$ 저장은 최고 34일, 상온$(10{\sim}15^{\circ}C)$ 저장은 8일까지 상품성이 유지되었으나, 무포장 상온보관은 3일 밖에 유지되지 않았다.

• 한국식품저장유통학회지
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• 제3권2호
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• pp.155-170
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• 1996

In order to determine the physiolosical characteristics of plum fruits(Oishi wase) during maturation and guilty according to temperature after harvest, (2-chloroethyl) phosphonic acid(ethphon) 390ppm was sprayed on plum tree 11days before commercial matuarity in Suwon area. And also this study was acted to investigate fruits quility(Formosa) influenced by temperature(room, low) and polyethylene films(0.03, 0.06, 0.1mm), 1. Effect of ethphon on the fruits maturation and fruits(Oishi wase) quility according to temperature ofter harvest. Ethephon stimulated fruits ripening but the firmness was reduced rapidly. Soluble solids and titratable acidity was not very different than each treatment. Carbon dioxide and ethylene production were advanced and the production peak were shown earlier by ethephon treatment as compared with control fruit. Anthocyanin development was enhansed rapidly by ethephon treatment but it exerted a bad influence on fruits color after harvest, The soluble sugars in fluits were mainly glucose, sucrose, and fructose. Those content were higher in treated fruit than control. The organic acid was mainly malic acid. The shelf life was less than about 5days at room temperature and about 10 days at low temperature. 2. Fruits(Formosa) quility as affected by polyethylene film bagging. The polyethylene films well maintained the firmness both room and low temperature. Low temperature was more effective in maintaining titratable acidity than room temperature, especially polyethylene films. On the Other hand, soluble solids content was not shown wide differance between room and low temperature. Polyethylene film showed a high resperation rate, the rate was higher at room temperature than low temperature and thicker films revealed higher rate. Otherwise, ethylene production was low in all treatment Polyethylene film inhibited the coloration of fruits, decreased anthocyanin content. Fruits coloration delayed by low temperature in control. The shelf life of plum fruits was about 6 days at room temperature and 13 days at low temperature in control Polyethylene film had no advantage on shelf life both at room and low temperature.

• 생물환경조절학회지
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• 제17권2호
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• pp.96-100
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• 2008

꼬투리째 먹는 채소인 풋꼬투리 강낭콩의 수확후 포장 및 저장 유통온도별 품질보존 및 상품성에 미치는 영향을 조사하였다. 저장중 중량의 변화에서 PP필름 포장시는 변화가 없었으나 골판지박스 포장시는 저장 온도가 높고, 저장기간이 길어질수록 중량 감소율이 현저하였다. 저장중 경도는 저온저장이 상온저장보다 높게 유지되었다. 비타민 C함량은 저장중 모든 처리에서 감소되었고, 그 감소의 폭은 상온저장보다는 저온저장 시 적었다. 엽록소함량은 비닐필름 포장시는 저장온도간에 차이가 없었으나, 박스포장시는 상온저장시 엽록소함량의 감소가 저온저장보다 컸다. 외관 상품성을 표시하는 신선도는 비닐포장이나 골판지박스에 속비닐 넣은 후 산물을 포장하여 $8{\sim}10^{\circ}C$정도에서 저장 유통시는 상품유지기간이 8일 정도로 상온보관대비 4일정도 연장되었다.

• Journal of Biosystems Engineering
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• 제25권2호
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• pp.107-114
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• 2000

Low temperature storage method is to increase the value of agricultural products by reducing quality loss and regulate consignment time by controlling respiration rates of agricultural products. Respiration rate of agricultural products depends on several factors such as temperature, moisture, gas composition and a microbe inside the storage room. Temperature is the most important factor among these, which affects respiration rate and causes low or high temperature damage. Fuzzy logic was used to control the temperature of a storage room ,which uses information of uncertain facts and mathematical model for room temperature control . Room temperature was controlled better by using fuzzy logic control method rather than on-off control method. Refrigerant flow rates and temperature deviations were measured for on-off system using TEV(temperature expansion valve) and for fuzzy system using EEV(Electrical Expansion Valve) . Temperature of the Storage room was lowered faster by using fuzzy system than on -off system. Temperature deviation was -0.6~+0.9$^{\circ}C$ for on-off system and $\pm$0.2$^{\circ}C$ for fuzzy system developed. Temperature deviation and variation of temperature deviation were used as inout parameters for fuzzy system. The most suitable input and output value were found by experiment. Cooling rate of the storage room decreased while temperature deviation increased for the sampling time of 20 sec.

• 한국초전도ㆍ저온공학회논문지
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• 제26권1호
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• pp.20-24
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• 2024

Over the past four years, as the COVID-19 pandemic has struck the world, cold chain of COVID-19 vaccination has become a hot topic. In order to overcome the pandemic situation, it is necessary to establish a cold chain that maintains a low-temperature environment below approximately 203K (-70℃), which is the appropriate storage temperature for vaccines, from vaccine suppliers to local hospitals. Usually, cryocoolers are used to maintain low temperatures, but it is difficult for small-scale local distribution to have cryocooler due to budget and power supply issues. Accordingly, in this paper, a cryogenic TSU (Thermal storage unit) system for vaccination cold chain is designed that can maintain low temperatures below -70℃C for a long time without using a cryocooler. The performance of the TSU system according to the energy storage material for using as TSU is experimentally evaluated. In the experiments, four types of cold storage materials were used: 20% DMSO aqueous solution, 30% DMSO aqueous solution, paraffin wax, and tofu. Prior to the experiment, the specific heat of the cold storage materials at low temperature were measured. Through this, the thermal diffusivity of the materials was calculated, and paraffin wax had the lowest value. As a result of the TSU system's low-temperature maintenance test, paraffin wax showed the best low-temperature maintenance performance. And it recorded a low-temperature maintenance time that was about 24% longer than other materials. As a result of analyzing the temperature trend by location within the TSU system, it was observed that heat intrusion from the outside was not well transmitted to the low temperature area due to the low thermal conductivity of paraffin wax. Therefore, in the TSU system for vaccine storage, it was experimentally verified that the lower the thermal diffusivity of the cold storage material, the better low temperature maintenance performance.

• 한국식품저장유통학회지
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• 제8권3호
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• pp.246-251
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• 2001

'창방조생 ' 과 '미백' 복숭아의 저장기간중 중량감모율은 상온무포장에서 4일후 각각 6.8%, 4.9% 이었으나 저온 (0~2$^{\circ}C$), 고습(95$\pm$3%) 조건에서 PE 무천공필름 포장저장구는 25일째 모두 1% 이내였다. 복숭아 저장중 경도변화는 상온에 비해 저온저장에서는 모두 큰 차이가 없었다. 두 품종 모두 저장기간중의 유기산과 가용성 고형분은 큰 차이를 나타내지 않았다. '칭방조생'과 '미백' 의 fructose, glucose 함량은 두 품종 모두 지장전보다 약간씩 증가였으나 Sucruse 함량은 25일 이후 감소하는 경향이었다. 복숭아는 30$\mu\textrm{m}$ LDPE fim 또는 25$\mu\textrm{m}$ SM60 film으로 포장하여 저온(0~2$^{\circ}C$), 고습(95$\pm$3%) 조건에서 저장할 경우 '창방조생'은 20일, '미백'은 25일까지 저장 가능하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권1호
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• pp.32-36
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• 2009

The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N$) of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25 wt% has the average phase change tempera ture of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

• 한국식품저장유통학회지
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• 제4권3호
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• pp.227-235
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• 1997

The internal breakdown of Fuji apple during CA storage classified as watercore breakdown, low temperature breakdown and CO2 injury. This study was undertaken to investigate the watercore breakdown injury factors of Korean Fuji apple during CA storage. The development of internal breakdown was more increased with the larger size, the later harvest time and the hither CO2 gas level. But in internal breakdown fruit of the titratable acidity and soluble solid decreased significantly, the pH of fruit juice and the production of carbon dioxide was greatly increased. The best gas levels of CA storage was 2% oxygen and 3% carbon dioxide. Thus, the predictable parameters of internal breakdown of fruit were increase in pH on decrease titratable acidity within 2 months of CA storage, increase carbon dioxide. So, it was found that the best CA sotrage for internal breakdown control of fruit during CA storage was delayed CA storage methods after low temperature storage immediate harvest of apple and than took a step. The delayed CA storage after low temperature storage for 2 months was more effective in the prevention of development of internal breakdown than immediate CA storage after harvest.

• 한국포장학회지
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• 제27권2호
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• pp.115-121
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• 2021

The evaluation of package temperature for fresh preservation of cucumber was investigated. The fresh cucumber is available in markets of Korea during whole seasons, for the help of farmer, distributor and consumer. Cucumbers were stored within cardboard boxes packaging covered with low density polyethylene (LDPE) at different temperatures (5, 10, 15 and 20℃). Changes in weight loss, hue angle, firmness, moisture content and general appearance (shape of cucumber) were investigated during storage of cucumbers. General appearance index with non-packaging decreased more than with LDPE film packaging at 5℃ and 10℃. During storage of cucumbers, general appearance index as freshness showed packaging effect at low temperature than room temperature. In the fresh weight loss, the packaged cucumbers were less reduced than that of the non-packaging ones. At color change, Hue angle of cucumber stored within low temperature with film packaging decreased gradually during storage. However remarkable change in hue angle were observed in cucumber within LDPE film packaging treatments of 15℃ and 20℃ storage. The effect of hue angle with packaging appears differently depending on the storage temperature conditions. The firmness and moisture content of cucumber flesh were not affected by packaging and storage temperature. In this experiment, cucumbers packaged with LDPE film at 5℃ and 10℃ were the most desirable for extending the quality. These results suggest that packaging of low temperature treatments in combination could be effective in prolonging the shelf life of cucumber.